Rheological properties of hydroxypropyl‐ and sodium carboxymethyl‐substituted guar gums in aqueous solution

TLDR: In this paper, the flow properties of guar gum polysaccharide solutions were studied in the range of low to moderately high shear rates, using a very simple technique and instrument.

Abstract: The aqueous solutions of guar gum and its hydroxypropyl (HP) and sodium carboxymethyl (sod CM) derivatives are pseudoplastic, and the transition from Newtonian to pseudoplastic occurs in the low-shear-rate range at the concentrations of interest to industries. The flow properties of these polysaccharide solutions were studied in the range of low to moderately high shear rates, using a very simple technique and instrument. The flow of these polysaccharide solutions can be described by equation of state based on Cross model, and the basic rheological parameters, like zero shear rate viscosity (η0), elasticity modulus (G0), and relaxation time (γ0), were calculated from simple and established relations. Master viscosity curves indicate that the molecular weight distribution of native guar gum has not been changed by derivatization. The effect of concentration and temperature on rheological parameters (η0 and γ0) has been studied, and the relations among these were established by simple equations.